Can you prove that God exists? Some of the greatest philosophers believed that it can be done. Anselm, Aquinas, Descartes, Leibnitz, Spinoza, Hartshorne, among others, all tried to do it.

They used different approaches. Some, like Thomas Aquinas, tried to try to prove God’s existence by arguing that the existence and design of the universe necessitate a God as its creator and ground.

One of Aquinas’ proofs, for example, goes this way: Imagine you’re walking along a road, see a stone lying on the ground, and someone asks you: “Who put that stone there?” You can easily answer that it’s always been there. Not much suggests that this is anything beyond brute nature. However, imagine you’re walking along that same road and you see a watch lying on the ground, still ticking, still keeping time. Could you still answer that it has always been there? Not so easily this time. Its intelligent design suggests that it’s not simply the result of blind nature, but the product of some intelligent designer, just as the fact that it’s still ticking makes it clear that it hasn’t always been there.

Aquinas then takes this image and extends it to the whole universe. Its intelligent design (for example, the central nervous system and brain structure of the human being) is a billion times more complex in terms of intelligent design than is a wristwatch and the fact that it’s running down tells us that can’t always have been here. Some intelligent designer must have helped fashion it and it must have had a beginning in time.

Descartes, Leibnitz, Spinoza, and Anselm have a different argument. Theirs goes this way: If God is possible, then God exists, because it is impossible to have a possible God. Since God is possible, God exists!

That may sound almost silly to the ordinary mind, but this peculiar little equation, expressed in different ways, has intrigued some of greatest minds on the planet, hinting that the rest of us, ordinary mortals, are perhaps missing something of its meaning.

The British philosopher, Frederick Copleston, in a famous debate with Bertrand Russell, once put all of these arguments into one equation: If the universe makes sense, then God exists. Russell, an atheist, actually conceded this truth, but then argued that the universe doesn’t make sense but is simply a brute, accidental fact that cannot be meaningfully explained.

What’s to be said about these “proofs”? Do they prove anything?

These are not mathematical or scientific equations and therefore don’t prove anything in that fashion. Nor are they arguments that compel a sceptic to believe in God. But that doesn’t mean they’re meaningless either. Their value is that they point to something deeper, beyond mathematics and science, something below the surface that invites you either to trust or doubt, to believe that it all makes sense or is meaningless. Their power is a moral power: Like how do you know if someone loves you? How do you know you can trust somebody? What gives you the feeling that life makes sense?

Karl Rahner once suggested his own proofs for the existence of God. For him, we taste God in certain experiences and these experiences ultimately imprint us with the belief that the universe makes sense, that we have sufficient reason to love and trust, that there’s a world beyond this one, and that there’s a God. Here’s a paraphrase of his argument:

Have you ever remained silent, though you wanted to defend yourself, though you were treated unfairly? Have you ever forgiven, though you received no reward for it and people took it for granted? Have you ever obeyed, not because you had to or else there would be some unpleasantness, but simply because of some mysterious, silent, unfathomable reality inside of yourself? Have you ever made a sacrifice, without receiving thanks, without recognition, without even feeling satisfaction inside? Have you ever been absolutely lonely and, within that, had to make up your mind to do something purely for the sake of conscience, from a place beyond where you can describe, from a place where you are deeply alone, and where you know you are making a decision for which the responsibility will be yours alone, always and eternally? Have you ever tried to love when no wave of enthusiasm was carrying you along, where you could no longer confuse your own needs with love? Have you ever persevered without bitterness in doing your duty when that duty looked like death, felt like it was killing you, looked stupid to those outside, and left you helpless to not envy those who have chosen a path with more pleasure? Have you ever been good to someone from whom no echo of gratitude or comprehension came back and where you weren’t even rewarded with the feeling that you had been good and unselfish?

If you’ve ever had any of these experiences, then you’ve experienced God and know that there’s a deeper ground beneath the one on which you walk.